From the Research
Ketamine is a safe and effective medication for managing trismus in patients with traumatic brain injury (TBI) secondary to trauma, and I recommend using it at a dose of 0.5-1 mg/kg IV as an initial bolus, followed by 0.1-0.5 mg/kg/hr as a continuous infusion if needed. The most recent and highest quality study, 1, suggests that ketamine does not increase intracranial pressure in TBI patients and may even have neuroprotective properties. This is consistent with other recent studies, such as 2 and 3, which found no evidence of harm from ketamine use in TBI patients.
When administering ketamine, it is essential to ensure continuous monitoring of vital signs, particularly blood pressure and intracranial pressure if possible. Ketamine works well in this setting because it provides both analgesia and muscle relaxation without significant respiratory depression, which is particularly important in TBI patients. Unlike benzodiazepines, ketamine generally maintains hemodynamic stability and preserves airway reflexes. The medication works by antagonizing NMDA receptors, which helps reduce muscle tone while providing pain control.
Some key points to consider when using ketamine in TBI patients include:
- Starting with lower doses and titrating carefully in patients with severe hypertension or known elevated intracranial pressure
- Monitoring for emergence phenomena and considering administering a small dose of midazolam (1-2 mg IV) if this occurs
- Being aware of the potential for ketamine to cause increased heart rate and blood pressure, and taking steps to mitigate these effects if necessary
- Considering the use of ketamine in conjunction with other medications, such as propofol or midazolam, to achieve optimal sedation and analgesia
Overall, the evidence suggests that ketamine is a safe and effective medication for managing trismus in TBI patients, and its use should be considered as part of a comprehensive treatment plan.